Self-drilling fasteners are used in all manner of construction. In a typical operation, a drill or other rotational driver is used to drive or rotate a fastener through a member such as drywall or a roofing panel into a substrate, such as a wall stud or roof joist. In some applications, torque is used to indicate proper joint tensioning or tightening. One drawback to using torque is that there is no correlation between the torque needed to drive a fastener and the proper tension or compression of a joint.
Moreover, the use of torque can be problematic for a number of other reasons. First, the torque needed to properly drive and seat a fastener into a workpiece will vary depending upon the members into which the fastener is driven. For example, driving a fastener into soft wood requires much less torque than driving a fastener into a hard wood. As such, when driving a fastener it is not unknown to strip the softer wood or to break a fastener when driving into a hard wood or into metal.
The use of joint compression or tension as determinant can be more difficult when components are present on a fastener. For example, when washers or grommets, particularly compressible, e.g., rubber or polymeric washers or grommets, are present under the head of fasteners to provide a seal, proper compression is difficult to determine and as such, the likelihood of over-driving or under-driving a fastener is increased.
Other devices and methods are known for determining proper driving and position of fasteners. For example, devices are known that operate on fastener/substrate position. However, here too, the presence of additional components on a fastener make such determinations problematic.
Accordingly, there is a need for a fastener drive and release system, a fastener and a method that serves to determine when a fastener is driven to a proper depth. Desirably, such a system and method uses a physical change in components of the system based upon joint compression, to carry out such a determination independent of the torque applied to the fastener. More desirably still, such a system and method stops the fastener driving movement and releases the fastener when a desired compression or tension is achieved. Still more desirably, such a system and method provides positive securement of the fastener during driving, up to release of the fastener.